Problem with SharedPreferences

Android
1

I tryed to save the string text of a button (id=language) but when the app starts the text become empty… can you help me?
Here the code:
package com.randomnumbers.dice

import android.content.Context
import android.media.MediaPlayer
import android.os.*
import android.view.View
import android.widget.Button
import android.widget.ImageView
import android.widget.SeekBar
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*
import kotlin.random.Random

class MainActivity() : AppCompatActivity() {

private lateinit var mp: MediaPlayer
private lateinit var mp2: MediaPlayer
private lateinit var mp3: MediaPlayer
private lateinit var mp4: MediaPlayer
private lateinit var mp5: MediaPlayer
private var totalTime: Int = 0

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val pref = getPreferences(Context.MODE_PRIVATE)
    val Language = pref.getString("Language", "")
    language.setText(Language)

    mp = MediaPlayer.create(this, R.raw.suono1)
    mp.isLooping = false
    mp.setVolume(0.5f, 0.5f)
    totalTime = mp.duration

    mp2 = MediaPlayer.create(this, R.raw.suono2)
    mp2.isLooping = false
    mp2.setVolume(0.5f, 0.5f)
    totalTime = mp2.duration

    mp3 = MediaPlayer.create(this, R.raw.suono3)
    mp3.isLooping = false
    mp3.setVolume(0.5f, 0.5f)
    totalTime = mp3.duration

    mp4 = MediaPlayer.create(this, R.raw.suono4)
    mp4.isLooping = false
    mp4.setVolume(0.5f, 0.5f)
    totalTime = mp4.duration

    mp5 = MediaPlayer.create(this, R.raw.suono5)
    mp5.isLooping = false
    mp5.setVolume(0.5f, 0.5f)
    totalTime = mp5.duration

    val rollButton = findViewById<Button>(R.id.rollButton)
    val resultsTextView = findViewById<TextView>(R.id.resultsTextView)
    val seekBar = findViewById<SeekBar>(R.id.seekBar)
    val language = findViewById<Button>(R.id.language)
    val Biscotto = findViewById<TextView>(R.id.Biscotto)
    val button = findViewById(R.id.rollButton) as Button
    val textView = findViewById<TextView>(R.id.textView)
    val dadoN1 = findViewById<ImageView>(R.id.dadoN1)
    val dadoN2 = findViewById<ImageView>(R.id.dadoN2)
    val dadoN3 = findViewById<ImageView>(R.id.dadoN3)
    val dadoN4 = findViewById<ImageView>(R.id.dadoN4)
    val dadoN5 = findViewById<ImageView>(R.id.dadoN5)
    val dadoN6 = findViewById<ImageView>(R.id.imageView11)
    val dadoN7 = findViewById<ImageView>(R.id.imageView13)
    val dadoN8 = findViewById<ImageView>(R.id.imageView12)
    val dadoN9 = findViewById<ImageView>(R.id.imageView14)
    val dadoN10 = findViewById<ImageView>(R.id.imageView15)


    language.setOnClickListener {
        if ("EN" == language.text) {
            language.text = "IT"
            rollButton.text = "Roll the dice"
            textView.text = "choose the number of dice:"
            if ("Lancia il dado" == Biscotto.text) {
                Biscotto.text = "Roll the dice"
            }
        } else if ("IT" == language.text) {
            language.text = "EN"
            rollButton.text = "Lancia il dado"
            textView.text = "imposta il numero di dadi:"
            if ("Roll the dice" == Biscotto.text) {
                Biscotto.text = "Lancia il dado"
            }
            fun onSave (view: View) {
                
        }
    }
        val pref = getPreferences (Context.MODE_PRIVATE)
        val editor = pref.edit()
        editor.putString("Language", language.text.toString())
        editor.commit()